Anticontact cap for x-ray tubes



Aug. 18, 1936. c. J. VAN VLlET ANTICONTACT CAP FOR X-RAY TUBES Filed Jan. 2, 1934 A ffwny Patented Aug. 18, 1936 UNITED STATES ANTICONTACT CAP FOR x tAY TUBES Cornelis Jan van Vliet, Eindhoven, Netherlands, assignor, by mesne assignments, to N. 'V. Philips Gloeilampenfabrieken, Eindhoven, Netherlands,

a Dutch company Application January? 1934, 'Serial-No. 704,984

In Germany January v3, 1933 4 Claims.

In order to support X-ray tubes at the middle, they are generally surrounded by a sleeve which may be grounded during the operation of the tube; which sleeve oitenextends sufficiently to surround the entire X-ray tube as a protective sheath.

With X-ray tubes provided with an anode which rotates during the operation of the tube, the magnet winding serving to drive the anode gave rise to inconveniences. Between this winding and the anode end of the tube there was observed a breakdown which could be prevented, for example by filling the air gap with an insulating material.

According to the invention, for this purpose use is made of a hollow body of solid insulating material, which body surrounds the tube at least over part of its length. This hollow body insulates the central part of the tube body from the sheath which surrounds the tube and which may be connected to ground, and in addition insulates from the other parts of the tube, the stator winding used to rotate the anode.

The presence of such a hollow body involves the slight drawback of weakening the X-rays which must pass through it. This drawback may, however, be reduced to a minimum by locally reducing the thickness of the hollow body in the vicinity of the window destined for the exit of the X-rays.

A preferred form of construction of the tube is characterized by an annular central metal part adapted to hold the hollow body and the stator winding serving to rotate the anode, and also to carry two detachable parts of the sheath which surround the ends of the X-ray tube.

The invention will be more clearly understood by referring to the accompanying drawing in which:

Figure 1 is a partly sectionized side view of an X-ray tube showing one embodiment of the invention;

Fig. 2 is a sectionized View of a portion of an X-ray tube showing another embodiment of the invention.

Referring to Fig. 1, the X-ray tube shown therein consists of two insulating neck-portions 1 and 2 serving for leading in the electrodes and sealed to one another by means of a central metal ring 3, provided with a window 4, to allow the X-rays to emerge from the tube.

The X-ray tube is surrounded by a metal protective sheath consisting of a central part 5, and two end parts l3 and I4. The metal sheath may be grounded during operation and afiords proof good insulating material.

the middle of the X-ray tube.

"tection against contact with parts of the tube under high tension. Instead of being made of metal the protective sheath may be of insulating material and be made conductive on at least one of its surfaces.

The high-voltage energy is supplied to the tube through high-voltage cables 9 and H! which are secured to the end parts l3 and I4 by sleeves i and 8 respectively. The cables 9 and ID are provided with a metal coating which is conductively connected to the metal of the promctive sheath.

in order to increase its resistance to electric voltages, the X-ray tube is surrounded-preterably throughout its lengthby a hollow body 6 The body 6 surrounds at least the central part of the body of the tube and insulates the X-ray tube from the sheath which is to be grounded, and also insulates the stator winding II and magnetic II is arranged between the hollow insulating body 5 and'the outer wall of. the protective sheath,

and within an annular hollow body I2, which body is supported by the central part 5 of the prometive sheath.

The two end parts l3 and It, which surround the ends of the X-ray tube, are detachably secured to the central part 5. Between the hollow insulating body 6 and the metal ring 3, there is provided a layer I5 of lead which prevents undesired X-raysfrom emerging from the tube.

To eliminate the electric field set up between the metal ring 3 and the insulating body 6, a metal film l6 should preferably be provided on the inner wall of the insulating body 6 and opposite The metal film i6 is conductively connected to the metal ring 3 by a contact spring (not shown).

Opposite the window 4, which serves for the exit of the X-rays, the metal sheath is provided with an aperture and with a flanged tube 23 to which a localizer l1, indicated by dotted lines, may be secured. Between the aperture defined by the tube 23 and the window 4, the insulating body 6 has a circular portion 24 of reduced thickness, for the purpose of lessening the absorption of the X-rays by the insulating body.

To insure a uniform distribution of the electric field within the protective sheath at the ends of the X-ray tube, the electrode supply conducwhosesurfacenis for the greater part concentric with the'end'surfaces of the 'end'portions I3 and M. V

V f 'Ifhe metal bodies'l8 and I9 may be ho o orderto allow for the supply of a liquid or gaseous cooling agent orlagain'they may; be solid in order to becapable of storing theheat; If in cept for the following: The protective sheath consists of two end portions l3"-' 'l 4 a central "portion 5, and an'annular' portion I2 all porview ofa' higher load, a-more-intense cooling should be desired, a small fan may'be arranged a cap 'atj one of the ends or the protective 'sheath," 7 Figure 2 shows a portion of a tube 'whosefcon- I struction is similar to that shown in Fig; 1 ex tion's being of'insulating material; The central portion 5 is providedwith an aperturefor the exit of the X-rays and has secured to it a flanged tube 23 (indicated in dotted lines), i

I4', annular portion l2, and central portion l5,

' are made conductivein known manner by means ofla coating 25 of 'conductivematerial,

What I' claim is: 1

sulating sleeve surrounding said tube and extending at least along the length of the anode,

and ametal protective sheath adapted to be grounded during the operation'of the tube surrounding; the tube and insulating sleeve, said sheath being formed withg'a hollow in which said stator is arranged; v r V 2. An X-ray' tube comprising an enclosing enannular body velope having a metal waist portion andvitreous portions sealed to each end of said waist'portion,

electrodes for said tube carried by said'vitreous. portions, a lead layer'on said waist portion; a cylinder of insulating material surrounding said I envelope and in spaced relationship therewith, a.

1 1. In an X-ray tube comprising anenclosing envelope and a rotary anode therein, an electro magnetic stator for rotating said anode, an in-,

tube.

spherical metalibody secured 'toeach end of said or tube and in contact with a corresponding electrode, said bodies having portions extending with a snug fit into'the'ends of said cylinder to support the tube from said cylinder,,a metal sheath surrounding said tube and cylinder and comprising a portion closely surrounding; that cylinder portion" which opposes the metal Waistportion; and serving to support said cylinder and tube,

said sheath'having flared portions with rounded "ends, said ends being substantially concentric with the metalbodies, and shockproof cables 7 secured to said flared portions for supplying high 7 voltage to said bodies and electrodes. 7

-3.-An' X-ray tube comprising an envelope an two electrodes within said envelope spaced to form a discharge gap substantiallyin'the center of the tube; an insulating cylinder surrounding 7 t 7 the tubeand in spaced relationship, thereto, a

conductive coatingonthe inner surface of said cylinder opposite pthe dischargel gap and having substantially the" same potential as the envelope portion opposite the discharge gap, 7 and a metal a sheath adapted to be grounded during the operation' ofrthe tube surrounding the cylinder and coating. a r V V a 4, An-X+ray tube comprising an enclosing envelope, a rotary anodeand 'a cathode mounted therein and spacedflapart to form a discharge gap, an electromagnetic stator for rotating said 'anode,"an insulating sleeve surrounding said'envelope' at least throughout the length of .said

discharge gap'and said anode, ancla protective metal sheath surrounding the sleeve and the tube- 'andhaving a central portion closely surrounding that-sleeve portion which opposes the discharge gap, said sheath being provided'opposite the rotary anodewith1 anannular portion containing said stator, said sheath having two flared portions', one being secured to said annular portion and the other beingsecuredto the opposite end 7 V of said centralportion, said flared portionshaving rounded endsarching over the ends of the a the tube, said, sheath closely surrounding said cylinderwhere it is provided withthe conductive I CORNELISJAN VAN VLJ IE'I'. 

